For many years the transportation industry has been concerned with designing hollow structural or other members that do not transmit or amplify noise from one portion of the vehicle to another, while also not adding significantly to the weight of the vehicle. One such technique has been to employ baffle structures, within hollow cavities of the space frame construction, for effectively blocking sound waves traveling through the sheet metal cavities. For instance, one popular technique has employed a baffle substrate that is coated or edged with a thermally polymeric material, which upon heat activation expands and fills the space defined between the substrate and a wall of the member. While these prior art devices perform well and are advantageous in many circumstances, they often require that the baffle substrate be shaped according to a predetermined configuration, which is generally dictated by the structure of particular sheet metal surroundings. In turn, this requires the manufacture of particular tooling for producing the substrate, which adds potential cost and delay, particularly if changes to the vehicle structure are implemented during the design stages. Accordingly, there is need for a simple low cost system that permits consistent and reproducible noise absorption within the vehicle cavities, and which can be employed across a wide range of different sizes or shapes of cavities.